Surfacing machine



April 7, 1953 c. A. ELLIS 2,633,675

SURFACING MACHINE Filed June 10, 1950 2 SHEETS--SHEET l INVENTOR.CHARLES A. ELUS ATTOK E Y April 7, 1953 c. A. ELLIS sURFAcING MACHINE 2SHEETS-SHEET 2 Filed June l0, 1950 INVENTOR. CH ARLES A, F.\ L\$ATTORNEE ou a Patented Apr. 7, 1953 UNITED STATES PATENT OFFICE AmericanOptical Company,

Southbridge,

Mass., a voluntary association of Massachusetts Application June 10,1950, Serial No. 167,420

is claims. 1

This invention relates to improvements in surfacing machines and hasparticular reference to improved apparatus for producing single orcompound curved surfaces on lenses or similar articles, and to animproved process for producing said curved surfaces.

One of the principal objects of this invention is to provide an improveddevice for forming substantially accurately shaped surfaces of single orcompound curvature on articles such as lenses and a novel method ofmaking same.

Another object is to provide an improved device for forming a single orcompound curved surface on an article such as a lens and of the typeembodying means for feeding a cup-type abrading tool transversely of thearticle whereby the plane of sweep of the tool produces a surfacecurvature in one major meridian having a radius substantially equal tothe radius of curvature about which the tool is moved and a surfacecurvature in the opposed major meridian dependent upon the angle atwhich the tool is disposed relative to the article during said sweep andfurther embodying means for altering the related position of the tooland article in a direction substantially normal to the plane of thesweep of the tool during said sweep.

Another object is to provide a surfacing machine of the above characterwherein the means for altering the related position of the tool andarticle in said normal direction causes movement about an axis which islocated in the plane of sweep of the abrading tool and at a distancefrom the surface being abraded substantially equal to the radius desiredof the surface curvature in said opposed maj or meridian.

Another object is to provide a surfacing machine of the above characterwhich will generate either concave or convex surface shapes on articlessuch as lenses.

Another object is to provide a surfacing machine of the above characterembodying means for feeding a cup-shaped abrading tool transversely ofan article being abraded with the tool being angled to present a rimportion thereof toward the article, which rim portion performs theabrading. and means for supporting the article for movement along anarcuate path substantially normal to the plane of sweep of the tool andfurther about an axis parallel to and lying in the plane of sweep of thetool whereby inaccuracies resulting from ellipticity of the effectiveabrading surface of the tool will be eliminated.

Another object is to provide a machine of the above character withsimple and efficient means for adjusting the tool and article for properpositlonment and for movement with respect to one another for generatingthe desired surface shape on the article.

Another object is to provide an improved hydraulic system forcontrolling the moving of the article to be abraded and its supportingmeans about a predetermined axis.

Further objects are to provide in a manner as hereinafter set forth asurfacing machine which is comparatively simple in its construction,durable, thoroughly eflcient in its use, and readily set up and adjustedfor providing articles such as lenses with various single or compoundsurface curvatures.

Other objects and advantages will become apparent from the followingdescription taken in connection with the accompanying drawings, inwhich:

Fig. l is a top plan view of a machine embodying the invention;

Fig. 2 is a fragmentary sectional View taken approximately on line 2 2of Fig. 1;

Fig. 3 is a perspective view of a lens of a type suitable for shaping inaccordance with the invention;

Fig. 4 is a fragmentary sectional top plan view illustratingdiagrammatically the respective positions of the abrading tool andarticle during the forming of a concave surface on the article;

Fig. 5 is a view similar to Fig. 4 illustrating the forming of a convexsurface on the article;

Figs. 6 and 7 are sectional views of lenses having concave and convexsurfaces respectively thereon;

Fig. 3 is a fragmentary side elevational view illustrating the movementof a lens and supporting means therefor when forming a concave surfacethereon, and

Fig. 9 is a fragmentary side elevation illustrating diagrammatically theengagement of a lens with an abrading tool when forming a convex surfaceon the lens.

Prior mechanical devices for generating a curved surface on an articlesuch as a lens have sometimes proven to be inefflcient because of thesomewhat complicated nature of the means used to adjustably position anarticle in abrading position in an abrading machine and to adjust theabrading tool for proper engagement with the article. The use ofcupped-type abrading tools which are angled to present a rim portion tothe article for abrading the surface thereof have proven to be mostsatisfactory with respect to simplicity and speed in generating surfacecurvatures particularly on articles such as ophthalmic lenses. However,such devices generally employ means for moving the angled tool in anarcuate path transversely of the article, which, due to the ellipticityof the effective surface of the tool, produces an inaccurate curvaturein the major meridian at right angles to the plane of sweep of the tool.

The present invention overcomes the above undesirable feature byproviding means for moving the article while in engagement with theabrading tool along an arcuate path substantially normal to the plane ofsweep of the tool as it moves transversely, whereby the surface of thearticle will be abraded accurately and simply to substantially thecurvature desired.

In following the teachings of the invention. it has been previouslystated that due to the ellipticity of the tool at different angularpositions of adjustment, there is an error in the curve generated in themajor meridian of the lens formed by the angle of the tool.

In generating minus curves, it has been found that the curvature as itmoves outwardly from the axis of the lens in that meridian of the lensformed by the angle of the tool deviates from the desired true curvaturein that the curve is generated to stronger curvatures which are of ashorter radius than that desired. In accordance with the presentinvention, an accurate curve in this direction is generated byoscillating the work or lens about a radius of curvature equal to thatdesired of the lens in said meridian during the movement of the toolabout the radius of curvature desired in the other major meridian of thelens. This oscillation is so controlled that the resultant curvature inthe meridian generated by the angle of the tool will be a substantiallytrue curve.

The true curve may be arrived at either by setting the tool to theproper angle required for theoretically producing this curve andcompensating for the error by oscillation as described above or byoffsetting the angle oi the tool from that required for the truetheoretical curvature slight amounts, and cooperatively arranging theoscillatory movement so as to arrive at said curve.

In generating plus curves on an article such as a lens in the meridianproduced by the angling of the tool, it has been found that the curve asit progresses inwardly from the margin of the lens toward the axis insaid meridian becomes progressively stronger than the nal true curvedesired.

In order to compensate for this condition the tool is so angled as toproduce a curve of greater radius than that of the final true curvedesired with said angle being so controlled that the curve formed in theaxial area of the lens is substantially that of the true curve desiredin said meridian of the lens and by oscillating the lens as stated abovethe curve as it progresses outwardly from said axial area toward themargin of the lens may be caused to assume the true curvature wherebythe resultant radius of curvature in said meridian will be substantiallythat of the true curve desired.

Referring more particularly to the drawings wherein like characters ofreference designate like parts throughout the several views, the machineillustrated in Figs. l and 2 is constructed and adjusted for productionof minus or concave surfaces on articles such as ophthalmic lenses andincludes means for supporting a lens or lens blank I for engagement witha cupped or ring-type abrading tool Il. The tool II is preferably of adiamond impregnated or charged type and is rotatably carried in aconventional manner by a motor I2 which is xedly mounted on a base plateI8. The base plate I3 is attached to a slide member I4 adjacent one endthereof by a pivot I5 and is rotatable about the pivot I5 on a raisedmachined track I6 provided on the upper surface of the slide member I4,and a lock screw I'I or similar means is provided to frictionally lockthe base plate I3 in adjusted position on the slide member I4, asindicated by a pointer i8 on the base plate I3 which is adapted to bealigned with the graduations on a scale Ia provided on the slide memberI4. By adjusting the base plate I3 in the desired position on the slidemember I4, the abrading tool II can be angled to present a rim portiondirected toward the lens I0 to be abraded. and this adjustment willdetermine the approximate curvature to be provided in one major meridianon the lens surface, in this case the vertical meridian.

The slide member I4 is mounted for movement longitudinally of themachine in a. guideway I9 provided therefor in the upper surface of abase 2U and adapted to be locked in position thereupon by means such asa lock screw 20a. The base 20 is rotatably secured to an adjustablesupport 2| by a pivot member 22. The support 2i is adjustablelongitudinally of the machine in guideways 23 formed in the uppersurface of the machine base 24. This adjustment is for the purpose ofpositioning the pivot member 22 at the desired distance from the pointof engagement between the lens blank I0 and tool IIl and the tool II andsupporting mechanism therefor is rotatable about the axis oi the pivotmember 22. Therefore, the radius of curvature to be generated in theopposed or horizontal meridian of the lens will be determined by thespacing of the pivot member 22 from a parallel line through the point ofengagement between the lens blank and tool and is indicated by a pointer25 on the support 2| which is adapted to be aligned with graduations onthe scale 26 on the machine base 24.

The preferred method of setting up the machine so as to generate thedesired curvatures in both the horizontal and vertical meridians is torst adjust the support 2I on the machine base 24 to position the pivotmember 22 as desired to establish the radius of sweep of the tool II.Then, after angling the tool by adjusting the base plate I3 on slidemember I4 to establish the radius of curvature in the vertical meridian.the slide member I4 is adjusted on the base 2) as described to positionthe effective abrading portion of the tool in engagement with thesurface of the lens blank I0 to be abraded. Then. upon operation of themachine, the motor I2 will cause the tool II to rotate and the entirehead mechanism will be swung about the axis of the pivot member 22either by manual or conventional automatic power to cause the tool I Ito arcuately traverse the lens surface.

The lens blank I0 which is to be surfaced by the tool Il is secured to ablock 21 by conventional means such as a layer of pitch 28 or othersuitable adhesive and the block 21 is suitably attached to the end of aspindle 29 which is positioned in e. longitudinal V-groove formed in theupper surface of a chuck 30. The chuck 30 is of any suitableconventional type, preferably magnetic, which will retain the spindle 29immovable in the V-grcove. To position the lens blank I for properengagement with the abradlng portion of the total I I, the spindle 23 isprovided with an extension 3| on its outer end. The extension 3l isadjustable longitudinally oi' the spindle 23 so as to control thedistance between the end thereof and the surface of the lens blank Hl.By providing such an adjustment the surfaces of lenses to be abraded canbe consistently maintained at a controlled distance from a stop arm 32on the chuck 30 against which the extension is positioned irrespectiveof variations in the thickness of the lens blanks.

This adjustment can be accomplished in many satisfactory ways. However,the preferred method is clearly shown and described in copending U. S.patent application Serial No. 792,668, filed December 19, 1947, nowPatent No. 2,548,418, dated April 10, 1948.

Suitable conventional mechanism (not shown) such as a micrometeradjustment can be used in connection with the spindle 29 or chuck 30 toadvance the lens blank Hi toward the tool for removal of controlledamounts of glass from the surface of the blank.

The foregoing description refers to a known type of mechanism used ingenerating simple or compound curves on the surfaces of articles such asophthalmic lenses. However, when angling an abrading tool I asdescribed, and sweeping it transversely across the surface of a lensblank l0, the ellipticity of the tool will cause the surface of the lensto be generated inaccurately in the vertical meridian, as indicated inFig. 6 wherein numeral 33 indicates the aspheric curve formed by thetool |9 and numeral 34 indicates the true spherical curve desired.

In accordance with this invention, in order to generate a surface havingan accurate curvature in the vertical meridian on a lens blank I0, ithas been found that this can be done by oscillating the lens blank alongan arcuate path substantially normal t0 the plane of sweep of the tooland about an axis located in the plane of the sweep of the tool and at adistance from the Surface being abraded substantially equal to theradius desired of the curvature in the vertical meridian.

The means for performing this operation embodies a rocker mechanismcomprising a pair of spaced arms 35 each having an end portion disposedadjacent the opposed sides of the chuck and adjustably attached theretoby studs 3B. The inner surfaces of the arms adjacent the chuck 30 areprovided with raised integral track-like portions 31 which arepositioned for sliding movement in longitudinal grooves providedtherefor in the sides of the chuck 30. The threaded studs 36 are beadedand each extends through a longitudinal slot 38 in the respective arms35 to provide means whereby the chuck 30 can be adjusted longitudinallyof the arms 35 and locked in desired position by tightening the studs 36and clamping the arms between the chuck and the heads of the studs.

The other ends of the arms 35 are provided with upwardly extendingportions 39 which are attached for coaxial pivotal movement to the upperends of stands 4| by pivot members 40. The lower ends of the stands 4Iare each provided wth enlarged portions 42 which are positioned forsliding movement in aligned slots 43 formed in the sides of the base 24so that the stands 4| and arms 35 may be adjusted longitudinally of themachine and held in adjusted position by means such as locking screw 42a6 (Figs. 1 and 8'). A short shaft 11 connects each o! the lower ends ofthe stands 4I to respective upturned end portions 78 of a biiurcatedmember 19. The bifurcated member 19 is provided with cross bars 80 forthreadedly receiving an operating shaft 8| which is rotatably carried inthe end of the machine base 24 and adapted to be rotated by means suchas crank 8|. Thus. upon rotation of the crank 8| the bifurcated member19 will move longitudinally of the machine and cause simultaneousresponsive longitudinal movement of the stands 4|, with the member 19also serving to retain the stands in preadjusted relative positions andconsequently the axes of the pivot members 40 in axial alignment. Thestands 4| may be locked in adjusted position by means such as knob 42awhich is threadedly mounted on one of the shafts 11 and can be turned toclamp the stands 4| against the sides of the base 24 in the conventionalmanner.

With this construction it is apparent that the lens can be made tooscillate about the axis of the pivot members 4D. It is important,however, that the pivot members 4B be located substantially in the planeof sweep of the tool and at a distance from the point of engagementbetween the lens and tool substantially equal to the radius of curvaturedesired in the vertical meridian. Thus, upon adjusting the stands 4| inthe slots 43 on the base 24 so as to establish the desired distancebetween the lens surface and the pivot members 40, the lens blank i0 canbe made to oscillate about the axes of the pivot members 4i) during theinitial abrading operation as the tool sweeps transversely of the lensblank or upon the return sweep of the head after completion of the firstabrading operation, or during a second traverse of the tool across thelens blank. In this manner, as the lens blank is osn cillated about theaxes of the pivot members 4|), the unwanted portions 44 of material,which are normally left on the lens blank, are removed since theseportions are made to engage and be abraded by the effective portions ofthe abrading tool I l approximating most closely the exact radius ofcurvature desired. In this way, an accurate surface can be abraded on alens blank or similar article.

The mechanism for causing the lens to oscillate embodies a pump 44 whichis adapted to force a suitable hydraulic fluid into a cylinder 45 forcausing operation of a piston 46, the pump and piston both beingpreferably located inside the machine base 24. The upper end of thepiston rod 46a extends through an opening 4l formed in the upper surfaceof the base 24 and has its upper end pivotally connected at 48 to thechuck 30. The lower end of the piston rofl 46a is provided with aconventional piston disc 49 which is shaped to snugly fit within thewalls of the cylinder 45. the cylinder 45 being pivotally connected atits lower end as at 5|), to a bracket 5| attached to the inner wall ofthe machine base 24. The pump 44 is comprised of a cylinder 52 having apair of diametrically opposed openings 53 and 54 therethrough to whichare connected one end of flexible conduits 55 and 55 respectively. theother ends of the conduits 55 and 53 being connected to the pistoncylinder 45 at points respectively above and below the piston disc 49.An eccentric 51 is disposed within the pump cylinder 52 and is adaptedto be rotated by an operating shaft 53. A pair of reciprocating plates59 and 6D are located in slots Bla and 62a respectively formed inenlarged portions 6| and 62 of the cylinder 52 and are adapted to engageopposed sides of the eccentric 51. Coiled tension springs 63 and 54 arealso provided in the slots to constantly urge the plates 59 and Btlrespectively toward the eccentric 51 and thus maintain them continuouslyin engagement therewith. In this manner there are formed two chambers 65and 66 within the cylinder 52. the chamber 65 communicating with conduit55 and chamber S6 communicating with conduit 56. Thus, upon rotation ofthe operating shaft 58 and consequently of the eccentric l in a.clockwise direction hydraulic fluid in the chamber 66 will be forced bythe eccentric through the conduit 56 into the lower portion of thepiston cylinder 45, urging the piston and consequently the lens and lensholding mechanism upwardly. As the eccentric continues to be rotated ina clockwise direction, Iiuid in the chamber 65 will be forced throughconduit 55 into the upper portion of the cylinder d5 to urge the piston46 downwardly, and thus cause the lens to be simultaneously moveddownwardly. The plates 59 and 60 by their reciprocating movementsprevent the uid from passing between the chambers 65 and 66.

With this construction the lens blank I0 can be easily and eflicientlymade to oscillate about the axis of the pivot members 40, asdiagrammatically shown in dotted outline in Fig. 8, and thus will causethe unwanted portions 44 of material to be removed from the surface ofthe lens as described.

Mechanism may be provided for restraining the lens supporting means frommovement and as shown in Figs. 1 and 2 comprise a pair of spacedbrackets 61 and 68 which are provided on the base 24 and are adapted toextend upwardly one on each side of the chuck 30. Screw clamps S9 andlll are provided in the upper ends of the brackets 61 and EBrespectively and are adapted to engage the sides oi the chuck torestrain it from movement when setting up the machine or when it isdesired to cause the tool to arcuately traverse the surface of the lensblank without causing simultaneous oscillation of the blank.

It is to be understood also that conventional devices not pertainingdirectly to the invention can be added to the machine if desired such asby providing the sides of the chuck 30 with cheeks or plates adapted,during oscillating movement of the work supporting head, to slidablyengage the screw clamps 69 and l0 to prevent the undesirable conditionknown as chattering Although the foregoing description refers to amachine set up and operated so as to form minus or concave surfaces onarticles such as lenses. it is within the scope of this invention toform plus or convex curved surfaces by modifying the construction of themachine so that the article will engage an inner abrading portion of theangled tool 1I. In such a machine the tool ll and article 14 (Figs. 5and 9) will both be movable about respective axes 12 and 13, which axesare both located rearwardly of the article 14 rather than forwardlythereof as in the minus curve generating machine.

In adjusting the machine to produce an accurate plus curve, the toolwill be located so as to sweep transversely of the lens for producingthe desired curvature in the horizontal meridian. Then, to adjust thedevice for generation ofthe curvature in the opposed or verticalmeridian, the tool is angled to the degree necessary for producing thedesired curve in the conventional manner. However, at this point thetool is further angled so as to produce a slightly weaker or atter curveand upon initially sweeping the tool transversely across the lens, itwill be understood that excess material will be retained by the lensadjacent the edges thereof as indicated by numeral l5 in Fig. 7. Thisexcess material 15 will be removed either during the initial sweep ofthe tool or subsequent thereto by oscillating the lens 'I4 about an axislocated at a distance from the surface being generated corresponding tothe radius of curvature desired in the vertical meridian. Thus, a truespherical curve 'i6 can be accurately formed on a plus lens.

In accordance with the foregoing description, it will be apparent thatthere is provided an improved device for forming a single or compoundcurved surface on an article such as a lens blank by providing means forfeeding a cup type abrading tool transversely of the article and meansfor moving said article along an arcuate path substantially normal tothe plane of sweep of the tool and thus producing accurate surfacecurvatures in both the horizontal and vertical meridians.

While certain novel features of the invention have been shown anddescribed and are pointed out in the annexed claims, it will beunderstood that various omissions, substitutions and changes in theforms and details of the device illustrated and in its operation may bemade by those skilled in the art without departing from the spirit ofthe invention.

I claim:

l. A surfacing machine for generating a curved surface on an articlesuch as a lens comprising a work supporting head for carrying an articleto be surfaced. and a tool supporting head adjacent said work supportinghead, an axially rotatable cup-shaped abrading tool mounted on said toolsupporting head and angled with respect to the surface of the article tobe abraded so that the portion which controls the resultant radius ofcurvature formed in one major meridian of the article will have linecontact therewith, said tool supporting head being mounted fortransverse swinging movement about an axis spaced from the effectivesurface of the tool an amount substantially equal to the radius ofcurvature to be generated on the article in one major meridian, and saidwork supporting head being mounted for pivotal movement in a pathsubstantially normal to the plane of sweep of the tool and about an axislocated in said plane of sweep of the tool, said axis of the Worksupporting head being disposed on the side of the article directedtoward the tool and at a distance from the surface to be abradedsubstantially equal to the radius of curvature to be generated on thearticle in the opposed meridian.

2. A surfacing machine for generating a curved surface on an articlesuch as a lens comprising a base, a tool supporting head on said base,an axially rotating cup-shaped abrading tool mounted on said toolsupporting head, and said tool supporting head being swingable about asecond axis disposed approximately normal to the axis of the tool andspaced from the eifective abrading surface of the tool an amountsubstantially equal to the radius of curvature to be generated on thearticle in one major meridian. said tool having its axis offset withrespect to the axis about which the tool supporting head is swingable sothat the portion of the tool which controls the radius of curvatureformed in one major meridian of the article will have line contacttherewith during the abrading action and supporting means for saidarticle comprising a stand carried by said base, a yoke pivotallyconnected to said stand, and carrying said article for arcuate movementabout the axis of said pivot, the axis of said pivot being located inthe plane of sweep of the tool and at a distance from the surface to beabraded substantially equal to the radius of curvature to be generatedin the opposed major meridian.

3. A surfacing machine comprising a base, a work supporting head locatedupon the base for carrying an article to be surfaced, locating mechanismon said base adjacent the work supporting head, a tool supporting headadjustably mounted on said locating mechanism for movement about a iirstaxis, means for supporting the article to be surfaced on said worksupporting head, an axially rotatable cup-shaped surfacing tool mountedon said tool supporting head with its axis approximately normal to saidfirst axis and with its effective abrading portion disposed adjacentsaid first axis, said locating mechanism being rotatable about a secondaxis parallel to said first axis, means for adjusting said second axisin directions toward and away from said work supporting head whereby thetool may sweep transversely across the article on a radius in accordancewith the curvature to be formed on the article in one major meridian,said tool supporting head being adjustable on said locating mechanismabout said axis of adjustment thereof to locate the tool in operativeposition with respect to the article and at an angle thereto inaccordance with the general curvature to be formed on the article in theopposed major meridian, and oscillating means operatively connected tosaid work supporting head for moving said article in an arcuate pathsubstantially normal to the plane of sweep of said tool on a radiussubstantially equal to the desired radius of curvature to be formed insaid opposed major meridian.

4. A surfacing machine comprising a base, a work supporting head locatedupon the base for carrying an article to be surfaced, locating mechanismon said base adjacent the work supporting head, an axially rotatablecup-shaped abrading tool having an eiective abrading portion of arcuateshape in section, a tool supporting head carrying said tool and beingpivotally connected to said locating mechanism for adjustment about afirst axis disposed approximately normal to the axis of the tool andpassing through said eiiective abrading portion thereof, means forsupporting the article to be surfaced on said work supporting head witha surface in position for abrading action by the tool, said locatingmechanism being rotatable about a second axis substantially parallel tothe pivotal axis of the tool supporting head and adjustable toward andaway from said first axis whereby the tool may sweep transversely acrossthe article on a radius in accordance with the curvature to be formed onthe article in one major meridian, said tool supporting head beingadjustable on said locating mechanism about said first axis to locatethe tool in operative position with respect to the surface of thearticle to be abraded and at an angle theretov in accordance with thegeneral curvature to be formed on said surface in the opposed majormeridian. and oscillating means operatively connected to said Worksupporting head forV moving said article in an arcuate pathsubstantially normal to the plane of sweep of said tool on a radiusadjustable to substantially equal the desired radius of curvature to beformed in said opposed major meridian, said arcuate movement ci thearticle being about an axis located in the plane of sweep of the tooland on the side of the article directed toward the tool.

5. A surfacing machine comprising a base, a work supporting head locatedupon the base for carrying an article to be surfaced, locating mechanismon said base adjacent the work supporting head, an axially rotatableabrading tool of ring shape and having an effective abrading surface ofarcuate shape in section a tool supporting head carrying said tool andbeing pivotally connected to said locating mechanism for adjustment ofthe tool about a rst axis approximately normal to the axis of the tooland intersecting the effective abrading portion thereof, means forsupporting the article to be surfaced on said work supporting head withits surface exposed for abrading action thereon, said locating mechanismbeing rotatable about a second axis approximately parallel to said firstaxis and adjustable toward and away from said first axis whereby thetool may sweep transversely across the surface of the article to beabraded on a radius in accordance with the curvature to be formed onsaid surface in one major meridian, said tool supporting head beingadjustable on said locating mechanism about said first axis to locatethe tool in operative position with respect to said surface of thearticle and at an angle thereto in accordance with the general curvatureto be formed on said surface in the opposed major meridian, andoscillating means operatively connected to said work supporting head andcomprising a stand carried by said base and adjustable toward and awaysaid work supporting head and having bearing portions for carrying saidwork supporting head for oscillating movement about the axes thereof.said axes of the bearing portions being located substantially parallelto and intersecting the plane defined by the sweep of the tool and onthe side of the article directed toward the tool.

6. The method of forming a curved surface on an article such as a lenscomprising supporting the surface of an article in line engagement withthe portion of an axially rotating cupped-type abrading tool whichcontrols the radius of curvature formed therein said tool being angledwith respect to the surface of said article in accordance with thegeneral curvature to be formed on said surface in one major meridian,feeding said tool in an arcuate path transversely across the surface ofsaid article about an axis spaced from the effective abrading surface ofthe tool an amount substantially equal to the radius of curvature to beformed on the surface of said article in the opposed major meridian, andoscillating said article while in engagement with said tool to providethe desired curvature on said surface of the article in the rst saidmajor meridian.

7. The method of forming a curved surface on an article such as a lenscomprising supporting an article for engagement with a cupped-typeabrading tool, rotating said tool while angled with respect to saidarticle in accordance with the general curvature to be formed on thearticle in one major meridian to cause the portion of the tool whichcontrols the resultant radius of curvature formed in one major meridianof the article to maintain line contact with the surface being abraded.feeding said tool in an arcuate path transversely across said articleabout an axis spaced from the effective abrading surface of the tool anamount substantially equal to the radius of curvature to be formed onthe article in the opposed major meridian, and oscillating said articlewhile in engagement with said tool about an axis located in the plane ofsweep of the tool to cause the article to move in an arcuate pathsubstantially normal to the plane of sweep of the tool on apredetermined radius to provide the desired curvature on the article inthe first said major meridian.

8. A surfacing device of the character described comprising awork-support and an axially rotatable ring-type abrading tool having aneffective abrading portion of arcuate shape in section, a tool supportsupporting said abrading tool for sweeping movement across the surfaceof the Work when in abrading relation therewith about an axis disposedsubstantially normal to the axis of rotation of the tool, said toolbeing so disposed on said tool support that its effective abradingportion which controls the resultant curvature formed in one majormeridian of the work has substantially line contact with the surface ofthe work during the abrading action, means for adjusting the spacingbetween said axis of rotation of the tool support and the surface of thework to be abraded to control the radius of sweep of the effectiveabrading portion of the tool across said surface of the work, said worksupport being mounted for movement about an axis disposed approximatelynormal to the axis of rotation f the tool support and lying within theplane defined by said sweep of the abrading portion of the tool acrossthe surface of the work, and means for causing oscillatory movement ofthe work support about its axis whereby a compound curvature may beformed on the surface of the work supported thereby controlled accordingto the radii of swing of the tool and the work about the axes of theirrespective supports while maintaining line contact between the surfaceof the work being abraded and said portion of the tool.

9. A surfacing device of the character described comprising awork-support and an axially rotatable ring-type abrading tool having aneffective abrading portion of arcuate shape in section, a tool supportsupporting said abrading tool for sweeping movement across the surfaceof the work when in abrading relation therewith about an axis disposedsubstantially normal to the axis of rotation of the tool, said toolbeing pivotally connected to said tool support for adjustment about asecond axis disposed substantially parallel with the axis of the toolsupport and passing through the effective abrading portion of the tool,means for adjusting the spacing between said axis of rotation of thetool support and said axis about which the tool is adjustable to controlthe radius of sweep of the effective abrading portion of the tool acrossthe surface of the work, said work support being mounted for movementabout an axis disposed approximately normal to the axis of rotation ofthe tool support and lying within the plane defined by said sweep of theabrading portion of the tool across the surface of the work, and meansfor causing oscillatory movement of the Work support about its axiswhereby a compound curvature may be formed on the surface of the worksupported thereby controlled according to the radii of swing of the tooland the work about the axes of their respective supports and the angulardisposition of the abrading tool about said second axis.

10. A surfacing device of the character described comprising a workholder and a support for said work holder, an axially rotatable ringtypeabrading tool having an effective abrading portion of arcuate shape insection, a tool support supporting said abrading tool for sweepingmovement across the surface of the work when in abrading relationtherewith about an axis disposed substantially normal to the axis ofrotation of the tool, said tool being pivotally connected to said toolsupport for adjustment about a second axis disposed substantiallyparallel with the axis of the tool support and passing through theeffective abrading portion of the tool, means for adjusting the spacingbetween said axis of rotation of the tool support and said axis aboutwhich the tool is adjustable to control the radius of sweep of theeffective abrading portion of the tool across the surface of the work,the work holder being movable on its support in directions toward andaway from said second axis to position the work within the sweep of theabrading portion of the tool. and said support for the work holder beingmounted for movement about an axis disposed approximately normal to theaxis of rotation of the tool support and lying within the plane definedby said sweep of the abrading portion of the tool across the surface ofthe work, and means for causing oscillatory movement of the work holderand its support about the axis of the support whereby a compoundcurvature may be formed on the surface of the work supported therebycontrolled according to the radii of swing of the tool and the workabout the axes of their respective supports and the angular dispositionof the abrading tool about said second axis.

11. A surfacing device of the character described comprising awork-support and an axially rotatable ring-type abrading tool having aneffective abrading portion of arcuate shape in section, a tool supportsupporting said abrading tool for sweeping movement across the surfaceof the work when in abrading relation therewith about an axis disposedsubstantially normal to the axis of rotation of the tool, said toolbeing pivotally connected to said tool support for adjustment about asecond axis disposed substantially parallel with the axis of the toolsupport and passing through the eective abrading portion of the tool.means for adjusting the spacing between said axis of rotation of thetool support and said axis about which the tool is adjustable to controlthe radius of sweep of the effective abrading portion of the tool acrossthe surface of the work, said work support being mounted for movementabout an axis disposed approximately normal to the axis of rotation ofthe tool support and lying within the plane defined by said sweep of theabrading portion of the tool across the surface of the work, a firstcylinder, a piston movable in said first cylinder and operativelyconnected with the work support. a second cylinder having a pair ofconduits connected to adjacent the opposed ends of said first cylinderon opposite sides of the piston, a rotatable member in said secondcylinder and a pair of reciprocating members cooperatively associatedwith each other to divide said second cylinder into a pair of chambers,each of said conduits entering a respective one of said chambers, andsaid rotatable member being of eccentric shape such that during itsrotation fiuicl may be forced out of one chamber through thecommunicating conduit while being restricted from the other toreciprocate the piston and move the work support about its axis acrossthe surface of the work whereby a compound curvature may be formed onthe surface of the work supported thereby controlled according to theradius of swing of the tool and the work about the axes of theirrespective supports and the angular disposition of the abrading toolabout said second axis.

12. A surfacing device of the character described comprising means forsupporting the work to be abraded, means for supporting a tool insurfacing action therewith, and a pivotally mounted support for at leastone of said means, a iirst cylinder. a piston movable in said firstcylinder and operatively connected with said pivotally mounted support,a second cylinder having a pair of conduits connected to adjacent theopposed ends of said first cylinder on opposite sides of the piston, arotatable member in said second cylinder and a pair of reciprocatingmembers cooperatively associated with each other to divide said secondcylinder into a pair of chambers, each of said conduits entering arespective one of said chambers, and said rotatable member being ofeccentric shape such that during its rotation fluid will be forced outof one chamber through the communicating conduit while being restrictedfrom the other to reciprocate the piston and the said supportoperatively connected therewith to obtain a surfacing action by the toolupon the Work.

13. A surfacing device of the character described comprising a pair ofsupports, one oi said supports embodying means for supporting work andthe other embodying means for supporting a tool, one of said supportsbeing axially rotatable, and the other of said supports being mountedfor movement about an axis disposed approximately normal to the axis ofrotation of the axially rotatable support, a. iirst cylinder, a pistonmovable in said irst cylinder and operatively connected with said othersupport, a second cylinder having a pair of conduits connected toadjacent the opposed ends of said first cylinder on opposite sides ofthe piston, a rotatable member in said second cylinder and a pair ofreciprocating members cooperatively associated With each other to dividesaid second cylinder into a pair of chambers, each of said conduitsentering a respective one of said chambers, and said rotatable memberbeing of eccentric shape such that during its rotation uid will beforced out of one chamber through the communicating conduit while beingrestricted from the other to reciprocate the piston and the said supportoperatively connected therewith, and means for adjusting the spacingbetween the axis of said support and the respective means carriedthereby.

CHARLES A. ELLIS.

REFERENCES CITED The following references are of record in the iile ofthis patent:

UNITED STATES PATENTS Number Name Date 1,199,519 Arnold Sept. 26, 19161,475,626 Galeski Nov. 27, 1923 1,800,308 Maynard Apr. 14, 19311,827,748 Holman Oct. 20, 1931 1,901,181 McCabe Mar. 14, 1933 1,984,074McCabe Dec. 11, 1934 2,278,314 Houchin Mar. 31, 1942 2,392,478 HolmanJan. 8, 1946

